Formation of Fe-embedded graphitic carbon network composites as anode materials for rechargeable Fe-air batteries

Abstract

This study reports on a composite consisting of iron (Fe) particles embedded in graphitic carbon network, which was prepared using a facile chemical synthesis method. The Fe-embedded carbon composite was used as the anode material for Fe-air batteries whose electrochemical charge-discharge performance was subsequently evaluated. The effect of adding 0.01M Na2S to the batteries' alkaline electrolyte on the electrochemical performances of the Fe-embedded carbon composite was investigated. The addition of Na2S to the electrolyte resulted in a higher discharge capacity during the charge-discharge characterization. A maximum discharge capacity of 486 mAh g−1(Fe) was obtained because sulfide ions present in the electrolyte inhibited Fe passivation, thus enabling a better redox reaction. Interestingly, after prolonged charge-discharge cycling (100 cycles), the replenishment of the 0.01M Na2S in the electrolyte resulted in the recovery of a high initial discharge capacity. The facile synthesis process, effect of Na2S addition, and the feasibility of discharge capacity recovery after prolonged charge-discharge cycling reported in this study should be beneficial toward the further development of rechargeable Fe-air batteries.